What am I to do?

The last words Jim said to me was “You’re dead to me”. He was my younger (18 months) and only brother. It was obviously a strained relationship due to his drinking. That was in February. Last Saturday morning, 9:03am (never gonna forget), I got that awful phone call. He hung himself on his ex-girlfriend’s back porch, out of spite, with an extension cord. I tried so long (34yrs) to help him but feel I’ve failed somehow for some inexplicable reason. I’m emotionally mixed up, like a rollercoaster and don’t understand why. Is there a support group available, one for sibling pairs who’ve experienced the loss of their other? Everything I find searching the ‘net assumes one has living parents. I don’t.